1. Field of the Invention
The present invention relates to an electronic device with display device, and more specifically relates to an electronic device for executing a plurality of programs via a single processor.
2. Description of Related Art
Conventional image forming apparatus such as, for example, copying machines and the like, use a plurality of control devices, e.g., microprocessing units (MPU) and the like which process at high speed and in parallel a plurality of control processes such as control processing for the mechanical portion of image formation, control processing for the optical unit for image formation, input control processing for each key and display control processing for the display portion, as well as control processing for the automatic document feeder (hereinafter referred to as "ADF") and the like. The aforesaid control devices further execute processing for cooperative execution of each of the aforesaid control processes via communication lines between the various aforesaid control devices.
However, the use of multiple control devices makes the entire control system become more complex, thereby requiring more complex software for operation. The aforesaid disadvantages increase the production costs for the system.
A further disadvantage occurs when a dynamic lighting type display device is used, inasmuch as the periodicity of the lighting of the display device cannot be uniformly maintained.
A still further disadvantage obtains when receiving data from other control devices while other control processes such as the display control process and the like are executing, inasmuch as the data from said other control devices cannot be received.
U.S. Pat. No. 4,343,036 discloses a copying machine having a special microcomputer to accomplish dynamic lighting of the display device. This arrangement has the disadvantage of increasing the cost of the apparatus due to the use of the aforesaid special microcomputer.